Wednesday, October 30, 2019

Observing Solar System Wonders

The Solar System is a true system, defined as a group of structures or elements which together form a functional unit. Science teachers incorporate the physics of energy and motion to explain how Solar System bodies move and remain in orbit. Visual (non-telescopic) astronomy affords impressive views of many objects in the Solar System. This includes six of the major planets—four terrestrial rocky planets, Mercury, Venus, Earth, and Mars, and two gas giant planets, Jupiter and Saturn. Two ice giant planets, Uranus and Neptune, are much larger than the four terrestrial planets, but smaller than the gas giants Jupiter and Saturn. Therefore, they are not generally visible without a telescope. Earth’s satellite, the Moon, constantly assumes different appearances as it revolves, waxing and waning throughout the lunar month. The Sun, the Solar System’s central star, also varies in elevation, intensity, and times of rising and setting due to Earth’s rotation and revolution.

Stars are not part of our Solar System, but the unaided eye may perceive over 2000 nearby stellar bodies presiding magnificently over Earth residents on a clear night, not to mention one or more Solar System planets visible on virtually any given night. They appear to be placed on the imaginary, infinitely distanced celestial sphere which surrounds Earth, a terrestrial planet also known as the terrestrial sphere.   

Many Solar System wonders are readily visible, but modern “light pollution” is an increasing handicap for envisioning objects on the celestial sky dome. We will recount several memories of Solar system wonders we offered to public school students during the last three decades of the 20th century. Prior to October each year we researched calendar dates of the dark phases of the Moon. We needed to know when the moon was not visible in our night sky. Those dates allowed for planning a dark sky “Star Watch” event for our astronomy students.

Dark skies facilitated observation of stars and planets. After a short talk in the gym by “Pastor Pete,” my own pastor, we proceeded outdoors for a group session to highlight visual identification of well known objects or star groups. I discovered that a flashlight with a narrow beam held as high as possible could direct student attention to individual stars, planets, constellations, and asterisms. We could instruct students concerning distances to selected stars. For example, in the asterism Summer Triangle which was dipping toward the west in October evening skies, we pointed out bright Vega, to our eyes’ fifth brightest star in the sky. It is a relatively close star at 25 light years. Also in the Summer Triangle is Deneb, about 1500 light years distant. It is a supergiant star, enormously larger and intrinsically much brighter than Vega, but appearing dimmer—only 19th brightest—because of its great distance.

Students were invited to view the skies through the pastor’s fine tracking telescope and several Astroscan telescopes owned by the school district. Several highlights were Jupiter with its four brightest moons, Saturn with its beautiful ring system, and Albireo, appearing as a single star to the naked eye, but resolvable even in a low power telescope to an impressive double star—one bright yellow, accompanied closely by a dimmer but incredibly blue-hued companion. Color indicated differences in stellar temperature.

The visible objects on those ‘watch’ evenings were all stars or planets within our home galaxy, the Milky Way. There was one exception. Some telescopes occasionally focused on Andromeda, a nearby neighbor galaxy. That “object” is really an entire galaxy of billions of stars in an apparently tightly bound group. It is visible as a tiny “fuzzy patch” through binoculars if one knows precisely where to look. It is sometimes called a twin of our Milky Way Galaxy. At two million light years distant, it is really 220,000 light years wide and contains as many as one trillion stars.

We pointed out circumpolar constellations and asterisms such as the Big Dipper, the Little Dipper, and Cassiopeia. These are star groups which never dip below the horizon at the latitude of New Jersey. They apparently revolve around the North Star, also known as Polaris. This famous star, sometimes called the Pole Star, is located directly above the geographic north pole of Planet Earth. The Earth’s extended axis never deviates from Polaris, day or night, summer or winter. Consequently, certain constellations such as the Big Dipper spend 24 hours apparently revolving around Polaris. This is caused by the real motion of Earth’s constant 24 hour rotation.

Following up on the above facts, our readers will understand our final instructions to students before they traveled home for a short night of sleep. Students were instructed to take note of the location of the Big Dipper. It was very low in the northern sky. Leading up to the star watch, students had been instructed to return to  school in pitch darkness the next morning. In Northern New Jersey, that means 5:43 AM on Oct. 21, for example. That hour corresponds with ‘astronomical twilight’ during which the sun is between 18º and 12º below the horizon. We enjoyed about one-half hour of darkness before the onset of dawn’s early light.

Students who arrived at 5:43 AM were able to view the Big Dipper, now high in the heavens. Earth had rotated substantially while they slept. The Big Dipper had apparently revolved to a position over their head, its handle now pointing toward the horizon! In addition a brilliant star field had become visible in southern skies, enclosed by an asterism of six bright stars named the Winter Hexagon. This phenomenon provided a convincing demonstration of Earth’s rotation. Our planet had rotated approximately 8000 miles eastward while students slept! 

Most male students took advantage of the opportunity to play touch football when they returned from the soccer field after observing the position of the Big Dipper and the new glory of stars enclosed by the Winter Hexagon. Most female students chatted in the cafeteria, waiting for the bagels prepared by their mothers. One year every student in our Earth Science classes attended both the evening and morning sessions even though their attendance was optional. Students were permitted to sleep in class that day, a privilege understandably forbidden on all other days.

The grandeur of the dark heavens was not lost on the students. In the initial group session “Pastor Pete” made reference to God’s vacuum cleaner, Planet Jupiter, whose strong gravity deflects harmful comets away from Planet Earth. The glory of God’s creation was apparent to all students and staff in attendance. Our star watches remain as cherished memories.   



Wednesday, October 23, 2019

Cosmic "Wow" Experiences

As we begin this post, clearing skies may provide opportunity to watch the Orionid Meteor shower which occurs in late October each autumn. The “shower” increases, then decreases in intensity from October 2 to November 7, but October 21 and 22 is the peak viewing opportunity. The annual event is but one of several dozen well known meteor showers. 

We are reminded of a unique event during childhood. On October 9, 1946, Earth residents in North America experienced an incredible meteor shower. I was privileged to view the shower resting on a hay wagon in the barnyard of my grandparents’ farm. My brother and I were enjoying the child-sitting skills of our grandparents that evening. At times not more than three seconds separated the meteor trails. Late in the evening our Grandmother insisted we “come in and go to bed” while the meteor show was still in progress—to the chagrin of her grandsons.  

We briefly review the cause of meteor showers. They originate from comets orbiting our sun. Wikipedia notes that 6339 comets were known as of July 2018, with the number of discoveries increasing steadily. Most of these originate in the nearby Kuiper Belt beyond the planet Neptune, but billions of comets still exist far beyond the Kuiper Belt in what has been dubbed the Oort Cloud. Comets are Solar System bodies composed of a mixture of small rocky particles, dust, and ice. When they approach the vicinity of the Sun, their ices vaporize from solar heat and form a much larger visible coma, sometimes forming a tail pushed away by the solar wind. When a comet passes through the vast reaches of space within our region of the inner Solar System, some dust or rocky particles remain behind as a thin trail of debris. Several dozen well-known comet trails crossing Earth’s orbital path remain from once active, visible comets of years past. They are the cause of meteor showers. Some comets leave behind denser debris than others; some trails strike Earth’s orbit more directly. We must understand that the “density” of comet trails is incredibly tiny. Predicting intensity of meteor showers is difficult. The 1946 meteor shower was caused by a comet named Giacobini-Zinner, discovered in 1900. Its debris still intersects with Earth October 6-10 each year, but peaks on October 8. The intensity of the October 1946 event had been forecast in August. Unusual circumstances make for unique, spectacular displays on rare occasions. The 1946 meteor spectacle is an example.

We opened this post by mentioning the annual Orionid Meteor shower, so named because its meteor trails seem to radiate from the star constellation Orion. Its origin is the famous Halley’s Comet. Tiny cometary left-over particles glow when they plunge at high speed into Earth’s atmosphere. They are consumed by frictional heat while streaking through the upper atmosphere at >45,000 mph. Then they are known as meteors. 

Halley’s is a famous periodic comet. It has appeared for hundreds of years every 75/76 years. It was first described as periodic by Edmund Halley in 1705. Researchers claim the periodic comet may have been seen before the time of Christ. Its fame is partly due to the precise predictability of its return visits. It made a famous appearance in 1910 when Earth actually passed through the comet’s tail. Its return in 1986 was hyped by commercialization, but its unspectacular appearance was disappointing. A New York Times reporter, Peter H. Lewis, later described the view of the comet as “small, fuzzy, and feeble.” I organized a bus trip to an observatory in Morristown, NJ with high hopes of seeing an impressive telescopic view of the famous comet. In February 1986 my students shivered in winter cold for at least 30 minutes while waiting in line for a brief look through a telescope at the famous Halley’s comet. In retrospect the bus journey did not result in a spectacular view of the comet. Still, the teacher remembers the experience as “worthwhile” and “meaningful.”

Following up on activities that are “worth it” in terms of effort, we must recount our personal action to recapture a small part of the Halley’s comet experience. We refer to the annual Orionid meteor shower with which we introduced this article. This morning (October 23) I rose at 4:30 AM, proceeded outdoors with a folding chair, and faced southeast toward the brilliant constellation of Orion. The thermometer indicated 38º F. Five meteors flashed through the heavens from the Orion radiant in 30 minutes; three were fairly bright, two were quite dim. Had no meteors been visible, we could still have perceived the divinely created glory of the autumn night sky. The “Winter Hexagon” is an incredibly rich star field enclosed by six bright stars. It is visible in the southeastern sky on early autumn mornings.
Media outlets frequently publicize annual meteor showers. Television meteorologists often combine news concerning meteor shower viewing opportunities with their weather forecasts. Comets and meteors provide opportunities for science minded Christians to highlight common and not so common environmental phenomena as manifestations of God’s characteristics—for example, His love and care for His created cosmic order. We are recapturing many other memories of cosmic “wow” experiences for future posts.     



Friday, October 18, 2019

Autumn Decline vs Potential for Renewal

Everyday conversations often begin with comments on the short and long term vagaries of the weather. Short term changes relate to rather sudden shifts. For example, one sunny summer or autumn day could be followed by stormy weather the next. Or, a cold front could lower the temperature substantially overnight. In contrast, seasonal shifts are noticed over several weeks or months. Potential for the first frost of autumn intensifies during late September or early October, with a killing frost possible by around mid October. Our current post relates to seasonal declines and how they relate to optimism for the future. 

(Our weather posts are based on your blogger’s residence in the Upper Midwest. All our lives we have resided close 40-42º N. Latitude. In more northern latitudes many meteorological and astronomical effects are intensified; in latitudes to our south effects are diminished. In the Southern Hemisphere the effects are reversed! Astronomical and meteorological statistics are available for tens of thousands of locations on Earth.)   

At this writing shortened day length and decreased sun angle are taking a toll on our temperatures in Northern Illinois. In the third week of October the lower sun angle contributes to weaker solar intensity. Day length has diminished more than four hours since the June 21 summer solstice. Sunrise is almost two hours later; sunset is more than two hours earlier. When winter solstice occurs on December 21, duration of daylight will be diminished about six hours. Solar heating from the sun’s radiation is less intense and occurs over a shorter time while Planet Earth radiates away more of its heat during the longer night. Average temperatures, therefore, fall when Earth loses more heat than it gains.

In January and February average temperatures do not fall any further. In the long term, Earth is generally losing its heat but gaining an equal amount from the Sun. Cold air masses move over the land more frequently and dominate our winter conditions. Air mass movements help generate meteorological variety. Winter weather enthusiasts are happy but some human “snow birds” escape to warmer climates at lower latitudes.

Generally stable, cold temperatures in January and February presage hope for those residents who prefer natural warmth. For them, help is on the way. Earth’s stable axis tilt results in increasing sun angles, earlier sunrises, later sunsets, longer days, and increasing temperatures as the planet continues its annual 365 day revolutionary cycle. At the December 21 winter solstice the Northern Hemisphere points farthest away from the Sun. Astronomers and meteorologists alike remind us that seasonal renewal is in prospect. One interesting sidelight is that significant temperature increases take about two months to become apparent. The general balance of heat gain and heat loss remains fairly even for weeks after the winter solstice. With increasing Sun angle, warmer temperatures will soon follow. Increased heat gain will predominate over heat loss. Future seasonal renewal is in prospect even during the decline of Autumn and the approach of cold winter months.

Our weather/astronomical system is a phenomenon of intricate beauty. Earth’s seasonal cycle has all the hallmarks of Intelligent Design. We do not shrink from proclaiming that the Intelligent Designer is the Creator of All Things. God has endowed living things with the potential to adjust to cycles of seasonal change. Some  plants and animals adapt to decreasing temperatures and remain in cold conditions all year long. Their perseverance is rewarded when warm seasons return. Many animals adapt by migrating seasonally. Inherently, they know what is best for their healthy survival.

Planet Earth is “a place to thrive.” Living creatures possess the God-gifted ability to manage and adapt to a broad range of environmental conditions, including seasonal changes. We are reminded of our ability to cope with changing seasons as we examine God’s statement to Noah in Genesis 8:22 (NIV): As long as the earth endures, seedtime and harvest, cold and heat, summer and winter, day and night will never cease.




Thursday, October 10, 2019

Autumn Farewell to Monarchs

Perhaps no insect commands more interest than Danaus Plexippus—the well-known Monarch butterfly. Its flashy physical appearance and distinctive migratory behavior locates this species in a special category. Our readers will bear with us for many past posts on Monarchs, the only butterfly to complete an annual two-way migration. 

Before discussing the migratory behavior of Danaus Plexippus, consider some developmental details of this unique animal. Our view is this migratory animal strengthens belief in an Almighty God who sustains the existence of all things. The monarch butterfly epitomizes the wondrous event sequence of four-stage metamorphosis. Adult female Monarchs, after mating with male monarchs, lay individual eggs on milkweed plants. A few days later, they hatch into tiny caterpillars, the larval stage, and begin to feed on milkweed leaves. After more than a thousandfold weight gain in one or two weeks, they suspend themselves upside down for a short time, shed their skin, and transition after 8-12 days into a beautiful jade-colored pupa called a chrysalis. The adult monarch which bursts forth from the chrysalis is a marvel of beauty. But the aesthetic beauty and four-stage metamorphosis of this insect is only part of its story.

Our current post is inspired by an observation we made from our Northwest Illinois front porch during the last week of September. Our residence faces almost directly east. We were privileged to observe a local manifestation of the famous migration of monarch butterflies. We noticed many monarch butterflies all flying above our front lawn from left to right. More precisely, we identified their compass direction of travel: northeast to southwest! I had not observed this directional monarch travel for a number of years. The last time was likely 2006. An encouraging spike in monarch population occurred in 2018—144% greater than the previous year. After many years of alarming declines, the increase is encouraging.  

A few days later we traveled to the east coast on Interstate 80—Illinois, Indiana, Ohio, and Pennsylvania. Again we observed every monarch navigating directionally across the Interstate from left to right. I estimated the number of monarch sightings as approximately 20 to 24 per hour. Every monarch was impelled to fly in a specific direction.

The last generation (probably the fourth) in late summer does not reproduce immediately. They return to Mexico after a long and hazardous flight to a small mountain forest. Their journey is followed by a long period of quiescence for several months with millions of other clustered monarchs. This special generation then begins a return journey a few hundred miles to the north. After reproduction, their offspring continue on, producing the second of four broods. Each of the first three broods lives only a few weeks. The fourth brood, from the northern and eastern states and southern Canada, undertakes a long, hazardous return journey at the end of summer to the mountainous Mexican forest. Diminishing day length and cooling temperatures trigger the fourth generation’s divergent behavior. Those travelers have never been to Mexico before!

Monarch migration is unusual because of its two-way, cyclical journey. In contrast, many individual migrating birds annually travel back and forth between their seasonal habitats. The difference between this bird migration and the unique monarch migration is that no individual monarch completes one cycle. In this way monarch migration is even more remarkable than bird migration. Monarchs must blend internal physiological and external cues such as earth’s magnetism, polarized light, and other geographical cues to implement their annual migration. Scientists have calculated that the pinpoint location of their Mexican overwintering forest site is only 0.015% of the area they occupy during their summer sojourn in the Eastern US and Canada.

Some bioscientists call the Danaus Plexippus migration an “evolutionary development.” We must determine the meaning of “evolutionary” in this context. The remarkable migration is necessary because the monarch is unable to survive in the cold, wintry, northern areas of its range. There are several world regions where monarch butterflies are non-migratory—namely southern Florida and smaller populations in Central and South America, Hawaii, South Pacific Islands, Australia, and a few spots in Western Europe. In all cases, we credit monarchs’ adaptability, also a gift of the Creator bestowed on living all things.

Epigenetic adaptation occurs “above or on top of” genetics—the basic information supplied by DNA to all living creatures. Not only does the monarch have a heritage of DNA, but it also has a heritage of epigenetic adaptation. Great quantities of information related to monarch behavior and all other living creatures are becoming accessible as new scientific discoveries uncover the genius of Our Creator.